1. Field of the Invention
The present invention relates to a pallet for carrying a sheaf of stacked planographic printing plates disposed thereon, and which is transported with the sheaf of planographic printing plates.
2. Description of the Related Art
An example of a pallet for carrying a sheaf of stacked planographic printing plates (e.g., photosensitive printing plates or thermosensitive printing plates) is disclosed in Japanese Patent Application Laid-Open (JP-A) No. 2000-118533. The pallet disclosed therein is made of corrugated cardboard in view of reducing manufacturing costs and simplifying recycling of the corrugated cardboard. The pallet comprises a mount on which planographic printing plates are stacked, a bottom panel disposed parallel to the mount, and legs disposed between the mount and the bottom panel to thereby connect them. An insertion member, such as a fork of a fork-lift, is inserted into gaps between adjacent legs, to lift and move the pallet.
Some production lines for manufacturing planographic printing plates include a stacking device. In such a production line, the planographic printing plates are cut to predetermined sizes and conveyed by a conveyor belt. Thereafter, the planographic printing plates are dropped one at a time from the conveyor belt and automatically stacked by the stacking device onto a pallet that is disposed at a predetermined position. In such a stacking device, the planographic printing plates that drop from the conveyor belt are cushioned by a stopper, lose their inertial force and are guided to the mount of the pallet by a guide plate. The mount preferably has a surface configuration (surface shape) the same as that of the planographic printing plates that are stacked thereon. The reason for this is because, when the surface shape of the mount is the same as that of the planographic printing plates stacked thereon, the accuracy with which the planographic printing plates are positioned and stacked in the surface direction thereof can be improved.
A predetermined number of planographic printing plates that are stacked on the mount may be packaged in a packaging paper so that they can be kept free from moisture and shielded from light. When the surface shape of the mount is the same as that of the planographic printing plates, ends of the packaging paper can be fastened, using an adhesive tape or the like, to side surfaces of the mount that has a fixed thickness. In this manner, the planographic printing plates can be packaged in the packaging paper with ease. In addition, since it becomes unnecessary to put adhesive tapes at edges of the planographic printing plates, it is possible to prevent adhesive on the tape from being transferred to the planographic printing plates, which can cause problems in quality.
However, in the pallet disclosed in JP-A No. 2000-118533, although the mount has a surface shape that corresponds to that of the planographic printing plates stacked thereon, the mount is fixed to the top panel of the pallet. Accordingly, it becomes necessary to use many pallets of different shapes in accordance with the varying sizes of the planographic printing plates that are produced in the production line. As a result, because many types of pallets are necessary and pallets of each type are manufactured in small quantity, manufacturing costs therefor inevitably increase. There is also a drawback in that the many types of pallets must be stocked in the plants at which the planographic printing plates are manufactured, which leads to poor efficiency in terms of managing costs and space utilization.
In view of the aforementioned facts, it is an object of the present invention to provide a pallet for stacking planographic printing plates thereon and with which it is not necessary to change pallets used for different sizes of planographic printing plates.
The pallet for stacking planographic printing plates thereon according to present invention comprises a pallet body, the pallet body including a top panel; amount, the mount including a top surface upon having a shape corresponding to the shape of the planographic printing plates stacked thereon, with the mount being mounted at a predetermined position on the top panel, such that a bottom surface of the mount contacts a top surface of the top panel of the pallet body; at least one recess disposed at one of the top panel and the mount; and at least one protruding member disposed at the other of the top panel and the mount, with the at least one protruding member being inserted into the at least one recess when the mount is mounted on the top panel, to thereby position the mount at the predetermined position and restrict movement of the mount in the surface direction of the top panel.
As a result, by using mounts having different sizes to correspond to different standard sizes of the planographic printing plates, any one of the mounts can readily be mounted on the pallet body. In this manner, even when planographic printing plates of different sizes are produced on the production line, by pre-mounting on the pallet body a mount having a size corresponding to the size of the planographic printing plates to be mounted on the mount, the planographic printing plate produced on the production line can be stacked on the mount having a corresponding surface shape. As a result, it no longer becomes necessary to use pallets of different sizes for planographic printing plates of different sizes. Only one type of pallet body can accommodate planographic printing plates of several sizes, thereby reducing manufacturing costs.
Note that the protruding member may be disposed at one of the top panel and the mount, and the recess may be disposed at the other of the top panel and the mount. Alternatively, both the protruding member and the recess may be provided at each of the top panel and the mount so that each pair of protruding member and recess correspond to each other. Further alternatively, a plurality of recesses and a plurality of protruding members may be provided.